When I connect only one monitor to the Asus gtx 660 ti-dc2o-2gd5, my PC
boots normally (I use the HDMI output).
But when I connect the second VGA monitor to the DVI port, the PC
doesn't boot and the monitors don't see any signal.
I have also a Display Port, but I can't use it because I don't have the
adapter.

Cristiano wrote:
> When I connect only one monitor to the Asus gtx 660 ti-dc2o-2gd5, my PC
> boots normally (I use the HDMI output).
> But when I connect the second VGA monitor to the DVI port, the PC
> doesn't boot and the monitors don't see any signal.
> I have also a Display Port, but I can't use it because I don't have the
> adapter.
>
> In the web I found nothing; do I need the DP connector?
>
> Thank you
> Cristiano

I don't run a dual monitor setup but i do run a gtx 660.
While messing around in the nvidia settings. I found this.
control panel -> nvidia settings -> manage 3D settings ->
multi-display/mixed-gpu accleration i have mine set to single display
performance.

There is an option for multipul display performance mode.

So i think that if you connect one monitor boot and then select the above
power down. Connect second monitor boot it should work. If you have all
ready done this ignor.

On 23/08/2013 13:06, Darklight wrote:
> I don't run a dual monitor setup but i do run a gtx 660.
> While messing around in the nvidia settings. I found this.
> control panel -> nvidia settings -> manage 3D settings ->
> multi-display/mixed-gpu accleration i have mine set to single display
> performance.
>
> There is an option for multipul display performance mode.
>
> So i think that if you connect one monitor boot and then select the above
> power down. Connect second monitor boot it should work. If you have all
> ready done this ignor.

The current setting is performance mode.

Anyway, the problem is not when I load windows, but when the PC tries to
boot.
If I connect the second monitor *after* the boot phase, it works, but if
I connect the second monitor *before* the boot phase, the PC hangs and I
don't see the POST (I can't access the BIOS).

Cristiano wrote:
> On 23/08/2013 13:06, Darklight wrote:
>> I don't run a dual monitor setup but i do run a gtx 660.
>> While messing around in the nvidia settings. I found this.
>> control panel -> nvidia settings -> manage 3D settings ->
>> multi-display/mixed-gpu accleration i have mine set to single display
>> performance.
>>
>> There is an option for multipul display performance mode.
>>
>> So i think that if you connect one monitor boot and then select the above
>> power down. Connect second monitor boot it should work. If you have all
>> ready done this ignor.
>
> The current setting is performance mode.
>
> Anyway, the problem is not when I load windows, but when the PC tries to
> boot.
> If I connect the second monitor *after* the boot phase, it works, but if
> I connect the second monitor *before* the boot phase, the PC hangs and I
> don't see the POST (I can't access the BIOS).
>
> Cristiano

How are you connecting the second monitor? What motherboard and cpu are you
using? I just put in "how to setup dual monitors" on youtube.
And saw two people setting up multipul monitor displays you might find help
to your problem there. Hope this helps.

Cristiano wrote:
> When I connect only one monitor to the Asus gtx 660 ti-dc2o-2gd5, my PC
> boots normally (I use the HDMI output).
> But when I connect the second VGA monitor to the DVI port, the PC
> doesn't boot and the monitors don't see any signal.
> I have also a Display Port, but I can't use it because I don't have the
> adapter.
>
> In the web I found nothing; do I need the DP connector?
>
> Thank you
> Cristiano

A poster here, flashed his video BIOS chip, and seems to have
a better working GTX 660 Ti. This isn't an Asus card, but
suggests perhaps NVidia provided a buggy BIOS for their
video card designs, and a newer BIOS is required.

On 24/08/2013 14:31, Paul wrote:
> Look under "BIOS", then "Version 1.0". Notice there is
> another file you can flash, but it's for usage of the
> video card, with a UEFI motherboard. And apparently you
> cannot revert that flash operation.

I flashed both VBIOS and BIOS, nothing changed. :-(
The last step is to try the DP/HDMI adapter...

Cristiano wrote:
> On 24/08/2013 14:31, Paul wrote:
>> Look under "BIOS", then "Version 1.0". Notice there is
>> another file you can flash, but it's for usage of the
>> video card, with a UEFI motherboard. And apparently you
>> cannot revert that flash operation.
>
> I flashed both VBIOS and BIOS, nothing changed. :-(
> The last step is to try the DP/HDMI adapter...
>
> Thank you all
> Cristiano

You have pretty strange symptoms.

I would not have thought the computer would hang,
as a result of the configuration of monitors connected.
It should still boot, as far as I know.

If I was testing adapters, I would go from DVI to HDMI.
The DVI port is the most likely to work. And DVI to
HDMI could be passive (and, limited to 1920x1200 or so).

On 25/08/2013 02:13, Paul wrote:
> You have pretty strange symptoms.
>
> I would not have thought the computer would hang,
> as a result of the configuration of monitors connected.
> It should still boot, as far as I know.

I think the same.
I don't know whether the problem comes from the "interference" with the
onboard VGA, but it seems strange to me. If I disable it, the problem
persists.
> If I was testing adapters, I would go from DVI to HDMI.
> The DVI port is the most likely to work. And DVI to
> HDMI could be passive (and, limited to 1920x1200 or so).
>
> "BYTECC DVI-HM DVI Male to HDMI Female Cable Adaptor"
> http://www.newegg.com/Product/Produc...82E16812270286

I already tried that adapter; the only port that I still didn't try is
the DP (because I don't have the adapter).

Cristiano wrote:
> On 25/08/2013 02:13, Paul wrote:
>> You have pretty strange symptoms.
>>
>> I would not have thought the computer would hang,
>> as a result of the configuration of monitors connected.
>> It should still boot, as far as I know.
>
> I think the same.
> I don't know whether the problem comes from the "interference" with the
> onboard VGA, but it seems strange to me. If I disable it, the problem
> persists.
>
>> If I was testing adapters, I would go from DVI to HDMI.
>> The DVI port is the most likely to work. And DVI to
>> HDMI could be passive (and, limited to 1920x1200 or so).
>>
>> "BYTECC DVI-HM DVI Male to HDMI Female Cable Adaptor"
>> http://www.newegg.com/Product/Produc...82E16812270286
>
> I already tried that adapter; the only port that I still didn't try is
> the DP (because I don't have the adapter).
>
> Cristiano

did you change the setting from 'performance mode' to 'multiple display
mode'?

On 26/08/2013 22:10, Darklight wrote:
> A thought came to mind. Regardless of the OS you are using, have you asked
> your question on a OS relevant news group. I assume you are using some
> version od windows?

It seems strange to me that you still don't understand that the OS has
nothing to do with my problem.

If the PC hangs *before* the POST, would you tell me, please, why do you
think that it's an OS problem?

Cristiano wrote:
> On 26/08/2013 22:10, Darklight wrote:
>> A thought came to mind. Regardless of the OS you are using, have you
>> asked your question on a OS relevant news group. I assume you are using
>> some version od windows?
>
> It seems strange to me that you still don't understand that the OS has
> nothing to do with my problem.
>
> If the PC hangs *before* the POST, would you tell me, please, why do you
> think that it's an OS problem?
>
> Cristiano

I am not saying it's the OS but i am sure that some one in an OS related
news group might have had this problem. And if so might be able to help.
What do you have to lose.

Darklight wrote:
> Cristiano wrote:
>
>> On 26/08/2013 22:10, Darklight wrote:
>>> A thought came to mind. Regardless of the OS you are using, have you
>>> asked your question on a OS relevant news group. I assume you are using
>>> some version od windows?
>> It seems strange to me that you still don't understand that the OS has
>> nothing to do with my problem.
>>
>> If the PC hangs *before* the POST, would you tell me, please, why do you
>> think that it's an OS problem?
>>
>> Cristiano
>
> I am not saying it's the OS but i am sure that some one in an OS related
> news group might have had this problem. And if so might be able to help.
> What do you have to lose.
>
> Ok just went on the net and found this hope this helps
>
> http://www.overclock.net/t/1384187/g...monitor-how-to
>
> This is some one who has the same problem you do
>
> http://forums.anandtech.com/showthread.php?t=2289726
>
> this is related to the above
>
> http://www.pcadvisor.co.uk/how-to/pc...-cables-apart/

The one additional symptom is though, the PC doesn't boot
with one of the connector choices. So it's worse than just
a "single nominated display" rule for BIOS usage.

I'd have said "defective card, send it back", but it
isn't normal for a display choice to cause a BIOS to
freeze up or stop the boot process. The BIOS should
load the VESA BIOS off the video card, and assume it
can run 800x600 or whatever, until the OS comes along
later and changes it.

UEFI could change that, as UEFI is more of a GUI thing.
And I don't really have much useful info on UEFI
boot differences (what matters to it). You would think
they'd still be using VESA BIOS info for that, but you
never know. Maybe a UEFI BIOS actually uses the
EDID info from the monitor ?

Even the notion, that one of the connectors on the
660 is DVI-I and the other one is DVI-D, is a
departure from the norm. I'm not aware of higher
end cards doing that. There are only a few cards,
that did strange things to their DVI connector
(there were some $30 cards, that split what would
normally be a DVI-I into a DVI-D and a VGA connector,
and were sort of sharing them - you couldn't use both
connectors at once, because they shared the same
EDID wiring). The end result, is the cheap cards
look like they're dual head, when in fact they
aren't. The card is functionally single-headed.
A 660 is well above the price range of such
stupidity.

*******

It just occurred to me, a BIOS setting of

Halt On [No Error]

might allow the BIOS to boot with the monitor
not functioning. The default is to have the BIOS
halt on certain errors, and using the [No Error]
option is the best way to get around a design defect.
I had a PC with a low-speed CPU fan, and that's how you'd
get it to boot without dropping into the BIOS. (The
BIOS thought the CPU fan was dead.)

Thank you very much for the link.
I finally realized that my stupid video card needs *digital* monitors to
boot with a dual-monitor (while, as I said, if I connect the second
monitor *after* the POST, anything works fine regardless of the type of
monitor).
To check that, I connected one monitor via HDMI - HDMI and the second
monitor via DVI-D - HDMI, then I boot and I see the POST message on the
DVI-D monitor without any problem.
> A 660 is well above the price range of such stupidity.

Cristiano wrote:
> On 27/08/2013 12:12, Paul wrote:
>>> This is some one who has the same problem you do
>>>
>>> http://forums.anandtech.com/showthread.php?t=2289726
>
> Thank you very much for the link.
> I finally realized that my stupid video card needs *digital* monitors to
> boot with a dual-monitor (while, as I said, if I connect the second
> monitor *after* the POST, anything works fine regardless of the type of
> monitor).
> To check that, I connected one monitor via HDMI - HDMI and the second
> monitor via DVI-D - HDMI, then I boot and I see the POST message on the
> DVI-D monitor without any problem.
>
>> A 660 is well above the price range of such stupidity.
>
> But my asus GTX 660-TI seems stupid enough. :-)
>
> Cristiano